Elevator systems have recently been provided with two features which are thought to save considerable passenger time and increase the carrying capacity of a given elevator installation. The first of these is utilizing destination calls, by which the passenger does not simply call an elevator to his floor, but at the same time informs the elevator of the intended destination floor. This allows the dispatcher (typically a suitably programmed computer) to allocate the call to the most appropriate car, taking into account not only the origin, but also the destination of the passenger.
A second feature causes passengers to enter their calls while still at some distance (equivalent to about ten seconds, in one case) from the elevator, whereby the dispatcher can attempt to cause the elevator to arrive at nearly the same time that the passenger reaches the elevator. In one case, the advance calls are entered by destination call buttons disposed remotely from the elevator in the passageways leading to the elevator. In other cases, the calls are entered either automatically by, or in response to pressing keys on, personal radio transmitters which transmit an identification (ID) number utilized to automatically enter a prearranged destination call or a key-selected call.
Typical problems with these systems include numerous false calls. Some of the false calls are caused by human error, particularly when ten-key entry panels are utilized, which is common in buildings having more than ten or twenty floors. Other false calls are registered as a consequence of pranks or vandalism. Still other false calls are caused by the person desiring to go to a destination other than his passively-entered, prearranged destination deciding not to enter the elevator yet (such as to purchase a newspaper on the way in) or simply changing his mind. Such systems have not had any adequate way to change calls, since there is a need to associate pressing of buttons on a destination call device with the ID number of a badge, the two of which are normally mutually exclusive ways of making calls. The use of destination call buttons, particularly in the landing during the morning rush, has been found to cause great delay in moving passengers onto the elevators, since typically lines are formed at each call entry panel. Because of the confusion and delay, passengers enter cars without having registered a call. In elevator systems utilizing destination hall calls, there typically is no car operating panel within each car, thereby providing no way to enter a car call once the passenger is in the car. Even if a car call could be entered in the elevator, the system would not know what previous destination call should be cancelled, since there is no way to associate the two. If one person simply cancelled a hall call or a destination call to some floor, other passengers wishing that service would lose it. If a passenger decides not to board or not to exit, the unnecessary floor stop unduly delays other passengers.